Tesco and Morrisons outpaced the other big four rivals in February, when overall grocery sales grew by more than 3% for the 12th consecutive month.
Both supermarket giants clocked up sales growth of 2.7% in the 12 weeks to February 25, according to the latest data from Kantar Worldpanel.
Tesco experienced particularly strong growth from its Extra superstores, despite a slight fall in market share of 0.1%.
Kantar head of retail and consumer insight Fraser McKevitt said: “The varied selection of groceries on offer at these larger stores has encouraged customers to return to fuller trolley shops.”
Morrisons’ market share held steady at 10.6%.
Aldi and Lidl once again battled to be crowned the UK’s fastest-growing supermarket. Aldi pipped Lidl to the post this month as sales advanced by 13.9% and 13.3% respectively.
Both discounters benefited from increased shopper numbers as well as growth in basket size.
Asda attracted an additional 309,000 shoppers during the period, helping the grocer achieve its highest sales growth since June 2014, at 2.3%.
Co-op returned to growth for the first time since July 2017, with sales up 0.4%, after a period of decline following the retailer’s sale of nearly 300 stores to McColl’s.
According to Kantar, overall grocery sales increased in value by 3.2% year-on-year, spurred by inflation, which now stands at 2.9%, and February festivities, such as Valentine’s Day and Chinese new year.
Alternative data from Nielsen anointed Tesco as the fastest growing of the big four supermarkets, with a sales increase of 3.1% in the 12 weeks to February 24.
Tesco was closely followed by Asda, which registered a 2.9% jump.
Overall, shoppers bought 0.8% more groceries last month year-on-year, Nielsen reported.
However, the increasing amount shoppers spent fell back slightly as inflation started to peak. Supermarket sales by value advanced 1.8% last month, compared with 2.7% growth in the same period last year.
Nielsen UK head of retailer insight Mike Watkins congratulated the grocers for displaying “a great balancing act at not passing on too much of the increased supply chain costs to the end shopper”.